A fuel filter or lubricant filter is disclosed in DE 10 2009 058 812 A1. The filter has an annular filter element that is flowed through in radial direction from the exterior to the interior by the fluid to be purified which subsequently is discharged axially out of the inwardly positioned clean space of the filter element. The filter element has correlated therewith a water separating device in the form of a coalescing element in which water, which is entrained in the fluid, is separated and subsequently is collected in a water collecting chamber. In coalescing elements, an agglomeration of dispersed small water droplets to larger droplets takes place; the latter, under their own weight, can flow out downwardly.
A multi-stage filter device for filtration of liquid fluids is disclosed in EP 1 932 570 4B1. The filter device has two annular, axially adjoining filter elements of which the first filter element is flowed through in radial direction from the exterior to the interior and the second filter element in radial direction from the interior to the exterior. On the side of the first filter element positioned inwardly in radial direction there is a water separating element that forms a lock for water droplets so that the water droplets will flow out along the water separating element.